Selector testing system



Sept. 12, 1933- w H SELECTOR TESTING SYSTEM Filed April 30, 1932 16 Sheets-Sheet 1 INVENTOR By J (DE/ W ATTORNEY Sept. 12, 1933. J w HN 1,926,894

SELECTOR TESTING SYSTEM Filed April 50, 1932 16 Sheets-Sheet 2 INVENTOR By J. W DEHN Sept. 12, 1933. J. DEHN 1,926,894

SELECTOR TESTING SYSTEM Filed April 30, 1932 16 Sheets-Sheet 3 A TTORNEY Sept. 12, 1933. w DEHN 7 1,926,894

SELECTOR TESTING SYSTEM Filed April 30, 1952 16 Sheets-Sheet 4 /N VENTOR J WDEHA/ A TTORNE V Sept. 12, 1933. w DEHN 1,926,894

SELECTOR TESTING SYSTEM Filed April 50, 1932 16 Sheets-Sheet 5 l/ENTOR J. W DEHN B V 6 12M A TTORNE V Sept. 12, 1933. J. w. DEHN 1,926,894

SELECTOR TESTING SYSTEM Filed April 50, 1932 16 Sheets-Sheet 6 4 T TOR/VE V Sep 12, 933- J. w. DEHN 1,926,894

SELECTOR TESTING SYSTEM Filed April 30, 1932 16 Sheets-Sheet 7 lNVENTOR JWDEH/V 6 BY A ORNE V Sept. 12, 1933. J. w. DEHN SELECTOR TESTING SYSTEM 1952 16 Sheets-Sheet 8 Filed April 30 //V|/EN TOR By J W. DEHN A TTORNEV Sept. '12, 1933; J. w. DEHN 1,926,894

SELECTOR TESTING SYSTEM Filed April 30, 1932 16 Sheets-Sheet 9 INVENTOR J. WDEHN BY A TTOPNE Y Sept. 12, 1933. J, w. DEHN SELECTOR TESTING SYSTEM Filed April 30, 1-932 16 Sheets-Shet 10 QQQ lNVENTOR J WDEH/V 8V A TTOR/VE V Sept. 12, 1933. J. w. DEHN SELECTOR TESTING SYSTEM Filed April 30,

1932 16 Sheets-Sheet 11 //v VENTOR J. W DEH/V er ATTORNEY J. W. DEHN Sept. 12, 1933.

SELECTOR TESTING SYSTEM 16 Sheets-Sheet 12 Filed April 3O 1932 mlllll-'.l-ll"ll" J WDEHN A TTORNEV 16 Sheets-Sheet 13 SELECTOR TESTING SYSTEM Filed April 30, 1952 E EEI a? EEEEE minim ummmmm Sept. 12, Y 1933.

A TTORNEV INVENTOR J. WDEHN IHHHHIH HIHIHIH SELECTOR TESTING SYSTEM Filed April 30, 1952 16 Sheefs-Sheet 14 POLAR/ZED lNVEN TOR J W DE HN BY 6. 6

Sept. 12, 1933. J. w. DEHN 1,926,894

SELECTOR TESTING SYSTEM Filed April 50, 1932 16 Sheets-Sheet 15 H HII lNVENTOR By J W. DEHN A TTORNE Y Sept. 12, 1933.

J. W. DEHN SELECTOR TESTING SYSTEM Filed April 30, 1932 16 Sheets-Sheet 16 INVENTOR J. W. DEHN Q6. A TTORNEV i atented Sept. 12, I933 Q I caries STATES Parser cssics SELECTOR 'rss'rnve SYSTEM .loseph W. Dehn, Brooklyn, N. Y.,' assignor' to-Bell Telephone Laboratories, Incorporated, New York, N. Y., a corporation of New York Application April 30,1932. Serial No. 608,381 21 Claims. (01. 17'9--1'2'5.21)

This invention relates to testing the operation sequence switch 800, the sender sequence switch of automatic telephone switching apparatus and of Fig. '7 corresponds to sequence switch 900, and has for its object to insure the proper performthe connector sequence switch of Fig. 8 correance of the charging function of such apparatus. sponds to sequence switch 1000. Similarly, brush More specifically the invention embodies an 810 is carried by the master selector which corautomatic routine testing arrangement for testresponds to switch 1910 of the Peoples patent.

ing all types of district selectors, but more espe- Brushes 820 and 830 belongto group selectors cially those which have equipment associated corresponding to group selectors 1710 and 1730, therewith by means of which charges are assessed brushes 8A0 and 841 belong to the connector se- 7 10 in accordance with the destination and duration lector corresponding to connector selector 1920 of calls. Such district selectors are provided with and brush 850 belongs. to the trouble timing means for recording the zone to which the call switch corresponding to the timing switch 1820. is directed and with means for measuring a defi- A district selector and message register connector nite time interval, together with means for apcircuit of the type shown in the above identified 15 plying charging current to the calling line under Johnston et a1. patent has been selected for the the joint control of the recording means and the, present disclosure. time measuring means. The testing device, A brief statement of the functioning of the therefore, has means for counting the number of test circuit and the selector will first be given. applications of metering current, means for When the operation of the test circuit is started 20 measuring the elapsed time and means for stopthe master selector, group selectors and connecping the progress of a call if the applications or" tor selector are positioned to connect the test. P metering current are wrong in number or in time circuit with the district selector in parallel with of application. the link circuit. A test is made to determine the District selector circuits of the type above mencondition of the district selector which may be 25 tioned are disclosed and claimed in'Patent No. busy, idle and awaiting selection by a link cir-' 1,859,924 granted May 24, 1932, to L. H. Johnson cuit, or idle and connected with a link circuit. t aL, in Pat n N 1,837,2 rant d Dec mber In the first case, the testcircuit Waits for the 22, 1931, to R. E. Collis, and in Patent No. selector to be restored to normal and then seizes 1,823,040 granted September 15, 1931, to A. E. it. In the second case, it seizes it immediately 30 Ha ue. A testing device i Which the p s and in the third case simulates a call which is testing arrangement is pted for use is disimmediately abandoned so as to free the district closed in U. S. Patent 1,650,721 to p selector from the link circuit. At the end of these granted November 29, 1927. operations the connector sequence switch of Fig. The invention will be more clearly understood 3 stands in position 8, The sender sequence 35 fr m a n id ra f the ll wi e er pswitch of Fig.7 next functions, first to cause the i n t r w the mp nyin rawin line finder to find the line finder test line, then in which": to position the district selector on the district Fi 1 to 8 disclose a p n f h test selector test line and finally to control talking secuit; lection after which it is advanced to position 18. 40 Fi 9 to 12 h w the m s r r n- The test sequence switch of Fig. 5 then takes up hector circuit; and its function and applies tests to the trunk con- Figs- 13 i016 Show the line finder and district ductors and the supervisory relays 1429 and 1431. selector circuits. The tests which form the subject matter of the The Circu s for testing the metering functions presentinvention are applied in position 6 of the of the district selector are essentially additions t sequence switch 50 to t testing featuresof the above identified The district class sequence switch of Fig. 4 is ples patent- In ge e theTefOre, y the positioned in accordance withthe type of class of testin f atu not Present in that pa have district selector with which the test circuit is been S w in the present diSCIOSU-IG- v connected. In all, there are seventeen classes of 50 13111130565 of reference i may be Stated that district selectors, depending on the kind of line the d str ot Class Sequence switch 4 p served. There may be flat rate lines, coin lines, forms the same funot as S qu Switch 3 and message irate lines, either individual ortwoof the Peoples patent. The test sequence switch party. In addition the selector may be equipped of Fig. 5 corresponds to sequence switch 600, the to charge for overtime or in addition may make a 55 test class sequence switch of Fig. 6 corresponds to multiple charge in accordance with a zone registration, applying an overtime charge for all zones but zero or for all zones but zero and 1. The district selector disclosed is one arranged to serve two-party message rate lines, to charge according to zone and to make an overtime charge in all zones but zero and in consequence when the test circuit is associated with this district the district class sequence switch of 4 is automatically advanced to position 17.

The test class sequence switch is positioned under the control of a set of keys, one for each test position and one or more tests may be made by operating the corresponding keys. When the connector sequence switch reaches position 8 the test class sequence switch is positioned for the first test call and is advanced from position to position at the termination of each test call. The test calls are the same as those described in the above identified Peoples patent, namely:

In position 1-call to an operator In position 2a non-charge call to a subscriber In position 3a charge call to a busy subscriber In position 4-an unanswered call In position 5a charge callline falsely grounded In position 6charge callsecond-party registration In position 7overflow In position 8call abandoned before district selections In position 9-call abandoned after district selections Of these test calls only those made in positions 3, 5 and 6 of the test sequence switch are of interest in this connection.

In preparation for testing selectors which are equipped for zone and overtime metering, one of the zone keys 110 to 115 must be operated, to set up the proper zone condition and key 222, if the overtime metering is also to be tested. These keys may be operated at the beginning of a routine test of all types of selectors since they only become effective in the proper positions of the district class sequence switch of Fig. 4.

As soon as the master selector is positioned a circuit is closed from ground over connector sequence switch cam 803, brush 810, winding of relay 865 to battery to connect the test circuit with the line finder test line on the frame served by the line finder under test. Relay 865 also operates relay 866 which closesa link in the fundamental circuit. When the district selector has been found idle and has been seized, the connector sequence switch of Fig. 8 is advanced to position 8 and relay 862 is operated to extend the fundamental circuit to the control of the sender sequence switch of Fig. 7. When the line finder test line is found relay 863 is operated, closing a circuit for relay 861 to the sleeve of the line finder test line which is connected to ground over the sleeve brush of the line finder, left back contact of relay 1506, resistance 1434, inner lower back contact of relay 1428, and the lower contacts of cam 1409.

Assuming that the fifth zone key 115 has been operated, when the test class sequence switch of Fig. 6 reaches position 3 a circuit is closed from ground over the lower contacts of cam 601, right contacts of cam 403, conductor 415 to the winding of relay 314 and in parallel therewith over the inner left contact of key 115 to the winding of relay 136. Relays 136 and 314 operate, relay 136 in turn operating relay 313. With relay 136 operated, during the time that the district selector is being operated to select the district selector test line, which takes place in positions 5 to 7 of the sender sequence switch of Fig. 7 and positions 4 to 6 of the district selector sequence switch 1400, a circuit is closed for operating the zone relays of the district selector from battery through low resistance 139, outer left contact of relay 136, upper contacts of cam 704, left contact of relay 862, contacts of cam 801, left contact of relay 866, brush 841, conductor 842, right contacts of cam 1406, right winding of relay 1625, left winding of relay 1626 to ground. Both relays 1625 and 1626 operate in this circuit and lock to ground over the lower contacts of cam 1409.

With the district selector sequence switch in position 12 and the sender sequence switch in position 17, a circuit is closed for making talking selection in the usual manner. This circuit may be traced from ground over the lower contact of cam 702, resistance 714, winding of stepping relay 719, right contact of relay 862, contact of cam 802, right contact of relay 866, brush 840, conductor 843, lower left contact of cam 1417, lower right contact of cam 1416, right winding of relay 1507 to battery. Relay 1507 looks over its inner right contact and the upper left contact of cam 1416 to the circuit above traced and closes a circuit from battery through the winding of sequence switch magnet 1400, lower right contact of cam 1420, left front contact of relay 1507, upper left and lower right contacts of cam 1614, right back contact of relay 1505, lower right contact of cam 1410. to ground, advancing sequence switch 1400 out of position 12. As the sequence switch passes through positions 12%, 13% etc., ground is connected over the left contacts of cam 1407 to the locking circuit of relay 1507, holding that relay operated and shunting the stepping relay 71.9.in the well known manner. Relay 719, when operated in series with relay 1507, closes a circuit from ground over the lower contacts of cam 703, front contact of relay 719, contact of cam 706, contacts of cam 602, front contacts of relay 314 and relay 313 to the winding of the No. 1 counting relay (not shown). Two shunting impulses are therefore necessary to satisfy the talking selection condition and the district selector comes to rest in position 14, while the sender sequence switch is advanced to position 18. In positions 17 and 18 relays 718 and 717 are operated in local circuits. The fifth zone key 115 thereforecauses sequence switch 1400 to be set in position 14 to complete the zone indication.

When the district selector has been positioned, the test sequence switch 500 tests the continuity of the test line and prepares for further tests. In position 4 of the test sequence switch a circuit is closed from battery over the right contact of cam 605, winding of relay 521, upper left and lower right contacts of earn 503, upper left contact of cam 604 to ground. Relay 521 locks over the left contacts of cam 503 through positions 4 and 5 to ground at its inner right contact. In positions 4 and 5 the calling supervisory relay 1429 is held operated in a circuit from ground through the upper left winding of repeating coil 1430, upper contacts of cam 1401, upper back contacts of relays 1428 and 1427, tip brush of the line finder 1303 and tip conductor of the line finder test line, inner rightcontact of relay 865,

brush of line finder 1303, lower back contacts of v relays 1427 and 1428, winding of relay 1429, upper contacts of cam 1403, lower left winding'of repeating coil 1430 to battery. At the same time, a busy back signal is transmitted to the called supervisory relay 1431, the circuit extending from ground over the left contactsof cam 601, upper right and lower left contacts'of cam 510,'tip of the district selector test line and tip brush of district selector 1320, upper contacts of cam 1402, upper right winding of repeating coil 1430, Wind'- ing of relay 1431, lower right winding of repeating coil 1430, upper contacts of cam 1404, ring brush of district selector 1320 and ring of the district selector test line, lower left and upper right contacts of cam 509, interrupter 513, outer right front contact of relay 521, resistance 522, right winding of relay 528, contacts of cam 60.7 to battery. Relay 523 operates in this circuit and looks through its left winding, back contacts of relays 525 and 524 to ground ever cams 505, 506 and 804.

This busy back operation is continued during an eight-second time interval as measured by relays 411, 412, 413 and interrupter 414. If the front contact of relay 1431 sticks during this time, premature charge will be made. The operation of the timing relays is briefly as follows: With the sender sequence switch in position 17 or 18, relays 718 and7l7 are operated and with the test class sequence switch in. position 3, ground is connected over the upper right contact of cam 601, outer right contact of relay 717, the back contacts of relays 412 and 413 to interrupter 414. When the test sequence switch reaches position 4 battery is connected over cams 605 and 501, to the winding of relay 411, right back contacts of relays 412 and 413, front contacts of relay 717 to the right contact of the interrupter 414. The next closure of this contact operates relay 411 which locks through the winding of relay 412 to ground overcarns 505, 506 and 804. opens its contact. With relay, 412 operated, ground is disconnected from interrupter 414 and battery is connected thereto from cam605 and the second closure of theright contact of interrupter 4 14 connects battery to the-right front contacts of relay 412 holding that relay, operated and shunting relay 411. With relay 411 released a new holding circuit for relay 412 is closed through the winding of relay 413 but relay 413 does not operate until the interrupter opens its contacts to remove batteryfrom the inner right contacts of relay 412. Relay 413 locks through resistance 418 to ground over cams 505, 506 and 804. With relay 413 operated, the interrupter receives ground over the back contact of relay 870.

When the interrupter closes its right contact for the third time relay 412 is shunted and released. At the following closure of the left contact of interrupter 414-relay 411 is reoperated closing a locking circuit for itself through the winding of relay4l2 as before. Relay 412 oper ates when the interrupter opens its contact. With relays 411, 412 and 413 operated a circuit is closed from battery through the winding of sequence switch magnet 500, lower right contact of cam 511, front contacts of relays 413, 412 and 411, front contact of relay 528 to ground at the left contacts of cam 601, advancing the test sequence switch to position 5' In passing from position 4 to position 5 thelocking-circuitfor relays 411 to 413 is opened at the upper l ft contact of cam 505 and these relays release. In position 5 the Relay 412 operates when the interrupter same cycle of operations is performed, advancing sequence switch 500 to position ,6 in which position the metering operations of the selector are tested.

. When the test class sequence switch was set in position 3 with the district class sequence switch in position. 17, relay 615 was operated over the upper left and lower right contacts of cam 403, lower contacts of cam 601 to ground, and in parallel with relay 615 a circuit extended over group selector brush830 to the winding of relay 864. Assuming that key 222 is operated to test for overtime charge, a circuit is also closed in parallel with the winding of relay 615 over the back contact of relay 205 and key 222 through the winding of relay 212 to battery.

Relay 864 connects the left windings of relays 716 and 715 to contacts of the first and second party multi-contact relays 1201 and 1202, respectively, so that they are ready to operate whenever metering current is applied. Relay 615 connects the front contact of relay 715 over the left back contact of relay 616 to the winding of relay 216 and the front contact of relay 716 over theright back contact of relay 616, back contacts of relays 206, 214, and 311 to the winding of relay 215 so that premature metering would operateone of these relays and block the test. Operation of relay 215 indicates the reception of metering current at the wrong time, while operation of relay 216 indicates that the wrong party relays have been operated so that metering current would have been applied to the wrong party meter. Relay 216 if operated locks over conductor 416, contacts of cams 401, 603, 505, 506 and 804 to ground, lights lamp 221, operates the trouble meter 805 and blocks the test by opening the circuit of magnet 307. Relay 215, if operated, locks to ground over the front contact of relay 615 and contacts of cams 505, 506 and 804 and lights lamp 220. It also sounds the alarm and blocks the test by opening the circuit of magnet 307.

When the test sequence switch 500 reaches position 6 a circuit is closed from ground over cam 804, lower left contact of cam 505, contacts of cams 603 and 401, conductor 416, winding of relay 316 to battery. A circuit is also closed from ground through the winding of relay 524, upper right and lower left contacts of cam 501 to battery over the left contacts of cam 605. Relay 524 substitutes battery over its inner right contact for battery through the winding of relay 528. It also prepares a circuit from battery over its left contact through the winding of relay 525, outer right front contact of relay 524, right contacts of calm 503, to ground at the inner righ contact of relay 521.

When sequence switch 500 advanced from position 5 the locking circuit of relay 521 was opened and relay 521 released. At the beginning of this test, a test is made of the ability of the district selectorv to hold over short openings of the line circuit and at the same time relay 1431 is subjected to heavy current how in the nonoperating direction. The circuit of the calling supervisory relay 1429 extends at the time that sequence switch 500 reaches position 6 over the path previously traced, while the circuit of the called supervisory relay 1431 is open.

As soon as sequence switch 500 reaches position 6 ground is connected over cams 508 and 606 to interrupter 617. When this interrupter closes its right contact it operates relay 612 which looks to ground over -cams 606 and 508. Relay 612, over acircuit not shown, advances the sender sequence switch to position 1. A circuit is then closed from battery through the winding of relay 613,

contacts of cam 705, outer right contact of relay 612, left contact of interrupter 617 to ground,

operating relay 613 which also looks to ground over cams 606 and 508. When the interrupter next closes its right contact relay 614 is operated over the front contact of relay 613 and locks to ground over the right contact of cam 507.

When relay 612 operated it closed the nonoperative circuit for relay 1431 which extends from battery over the right contact of earn 605, left front contact of relay 612, resistance 527, left back contact of relay 521, lower contacts of cam 510, over the tip of the district selector test line through relay 1431 as previously traced to the ring of the test line, lower contacts of cam 509, right back contact of relay 521 to ground over cams 506 and 804. When relay 613 operated it opened the holding circuit above traced for relay 1429, which was in shunt of resistances 720 and 618 and the winding of relay 611. These resistances are sufficiently high to release relay 1429. When relay 614 operates the holding circuit for relay 1429 extends as previously traced from the tip conductor to earn 512 and thence over the front contact of relay 614, contacts of earn 514, to the ring conductor, again shunting resistances 618 and 720 and relay 611..

Relay 614, in operating, closes a circuit from ground at its inner left contact, right front contact of relay 316, inner right back contact of relay 318, winding of relay 213 to battery. To initiate the operation of the timing switch, relay 213 closes a circuit from battery through the winding of magnet 307 of the primary timing switch 300, back contacts of relays 201, 216, 214, 215, 206 and 210, inner right front contact of relay 213, inner left back contact of relay 212 to ground over interrupter 211.

Interrupter 211 which is common to the ofi'ice, is driven by the same mechanism as interrupter 1208 which controls the timing function of the district selector so as to be in synchonism with it, but closes its contact once every six seconds. When the interrupter closes its contact magnet 307 operates and when the contact opens advances switch 300 to position 1. In this position a circuit is closed from battery through the winding of relay 311, left contacts of cam 406, normal contact of brush 101 of the secondary timing switch 100, and in parallel therewith from battery through the winding of relay 315, brush 305 in position 1, outer right back contact of relay 210, outer left front contact of relay 212 to ground at the inner right contact of relay 213.

elay 315 locks to ground over the front contact of relay 615 and the right contact of cam 505. Relay 311 disconnects the front contact of relay 716 from the winding of relay 215 and connects it to the winding of relay 312 to receive the metering impulses.

Relay 315 closes a circuit from ground at its outer right contact, left front contact of relay 316, left contacts of cam 503, winding of relay 521, right contact of cam 605 to battery. Relay 521 reoperates in this circuit and looks as before, transferring the circuit of relay 1431 to battery and ground in a direction to operate that relay. The tip of the test line now extends over the outer left front contact of relay 521 through resistance 526 to ground over the left contact of cam 702 and the ring of the test line extends over theright front contact of relay-521, resistance 522, to battery at the inner right contact of relay 524. It is therefore apparent that the advance of switch 300 to start the timing causes the operation of relay 1431.

In the district selector, the operation of relay 1431 connects ground from the right contacts of cam 1409 over the front contact of relay 1431, upper contacts of cam 1414, right contacts of cam 1603 to interrupter 1514. When the interrupter closes its right contact, it extends this ground over the right contacts of cam 1606 through the right winding of relay 1508 to battery. Relay 1508 closes a locking circuit for itself over its outer right contact to the same ground. When the interrupter closes its left contact, two seconds later, ground from the front contact of relay 1431 is extended over the inner right contact of relay 1503, lower contacts of cam 1423, right contacts of cam 1602, lower left contact of cam 1622 to battery through the winding of sequence switch magnet 1600. The district selector timing sequence switch 1600 is therefore advanced to position 2, disconnecting ground from interrupter 1514 and releasing relay 1503.

With sequence switch 1600 in position 2 a circuit is closed for relay 1501 over the left contacts of cam 1606, upper left contact of cam 1411 to ground. Relay 1501 extends its operating circuit to the winding of relay 1502 which locks over its inner left contact to ground at the upper left contact of cam 1409, holding relay 1501 operated.

With sequence switch 1600 in position 2, the district selector prepares to seize the message register connector circuit. For this purpose a circuit is closed from ground over the front contact of relay 1431, upper contacts of cam 1414, upper contacts of cam 1603, right winding of relay 1624 to conductor 1627. In the connector circuit this conductor extends, if the circuit is idle, over the right back contact of relay 1114, left back contact of relay 1016, upper back contact of relay 912, winding of relay 1115, left back contact of relay 1015 to battery. If the connector is busy, this circuit is opened at one or more points and the district selector waits until it becomes idle. When this occurs relay 1624 operates and prepares a locking circuit for itself from battery through its left winding, upper left and lower right contacts of cam 1617, right front contact of relay 1624, left back contact of relay 1114, winding of relay 1015, lower back contact of relay 912 to ground. A preference circuit over the contacts of relays similar to relay 1624 in other district selectors gives them access to, the connector in a given order, if more than one attempt to seize the connector at the same time.

When relay 1624 looks, relay 1015 operates in turn operating relays 1014 and 1016. Relay 1623 also operates in parallel with the locking circuit of relay 1624 and operates relay 1512.

With relay 1512 operated the first party relay of the connector circuit is operated over a circuit which may be traced from battery through the windings of relays 1009 and 1001, conductor 1515, inner right contact of relay 1512, right back contact of relay 1511, outer right contact of relay 1512, right contacts of cam 1412, commutator strip 1315, brush '1312 to ground. Relay 1001 in turn operates relay 1201 and a plurality of similar multi-contact relays in order to connect the first party meters to the metering terminals of the corresponding lines in the frame served by the connector circuit and district selector. Relay 1201 in turn operates relay 1203, two multi-con- 

